NAT: Twice NAT44 (VPP-969)

Translation of both source and destination addresses and ports for 1:1 NAT
session initiated from outside network (ExternalIP K8 use case).

Change-Id: Ic0000497cf71619aac996d6d580844f0ea0edc14
Signed-off-by: Matus Fabian <matfabia@cisco.com>

1 files changed, 172 insertions, 5 deletions

diff --git a/test/test_nat.py b/test/test_nat.py
index 36163297961..1f87bffab57 100644
--- a/test/test_nat.py
+++ b/test/test_nat.py
@@ -737,7 +737,9 @@ class TestNAT44(MethodHolder):
 
         interfaces = self.vapi.nat44_interface_addr_dump()
         for intf in interfaces:
-            self.vapi.nat44_add_interface_addr(intf.sw_if_index, is_add=0)
+            self.vapi.nat44_add_interface_addr(intf.sw_if_index,
+                                               twice_nat=intf.twice_nat,
+                                               is_add=0)
 
         self.vapi.nat_ipfix(enable=0, src_port=self.ipfix_src_port,
                             domain_id=self.ipfix_domain_id)
@@ -770,6 +772,7 @@ class TestNAT44(MethodHolder):
                 addr_only=sm.addr_only,
                 vrf_id=sm.vrf_id,
                 protocol=sm.protocol,
+                twice_nat=sm.twice_nat,
                 is_add=0)
 
         lb_static_mappings = self.vapi.nat44_lb_static_mapping_dump()
@@ -778,7 +781,8 @@ class TestNAT44(MethodHolder):
                 lb_sm.external_addr,
                 lb_sm.external_port,
                 lb_sm.protocol,
-                lb_sm.vrf_id,
+                vrf_id=lb_sm.vrf_id,
+                twice_nat=lb_sm.twice_nat,
                 is_add=0,
                 local_num=0,
                 locals=[])
@@ -798,6 +802,7 @@ class TestNAT44(MethodHolder):
         for addr in adresses:
             self.vapi.nat44_add_del_address_range(addr.ip_address,
                                                   addr.ip_address,
+                                                  twice_nat=addr.twice_nat,
                                                   is_add=0)
 
         self.vapi.nat_set_reass()
@@ -806,7 +811,7 @@ class TestNAT44(MethodHolder):
     def nat44_add_static_mapping(self, local_ip, external_ip='0.0.0.0',
                                  local_port=0, external_port=0, vrf_id=0,
                                  is_add=1, external_sw_if_index=0xFFFFFFFF,
-                                 proto=0):
+                                 proto=0, twice_nat=0):
         """
         Add/delete NAT44 static mapping
 
@@ -818,6 +823,7 @@ class TestNAT44(MethodHolder):
         :param is_add: 1 if add, 0 if delete (Default add)
         :param external_sw_if_index: External interface instead of IP address
         :param proto: IP protocol (Mandatory if port specified)
+        :param twice_nat: 1 if translate external host address and port
         """
         addr_only = 1
         if local_port and external_port:
@@ -833,18 +839,21 @@ class TestNAT44(MethodHolder):
             addr_only,
             vrf_id,
             proto,
+            twice_nat,
             is_add)
 
-    def nat44_add_address(self, ip, is_add=1, vrf_id=0xFFFFFFFF):
+    def nat44_add_address(self, ip, is_add=1, vrf_id=0xFFFFFFFF, twice_nat=0):
         """
         Add/delete NAT44 address
 
         :param ip: IP address
         :param is_add: 1 if add, 0 if delete (Default add)
+        :param twice_nat: twice NAT address for extenal hosts
         """
         nat_addr = socket.inet_pton(socket.AF_INET, ip)
         self.vapi.nat44_add_del_address_range(nat_addr, nat_addr, is_add,
-                                              vrf_id=vrf_id)
+                                              vrf_id=vrf_id,
+                                              twice_nat=twice_nat)
 
     def test_dynamic(self):
         """ NAT44 dynamic translation test """
@@ -2857,6 +2866,164 @@ class TestNAT44(MethodHolder):
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
+    def test_twice_nat(self):
+        """ Twice NAT44 """
+        twice_nat_addr = '10.0.1.3'
+        port_in = 8080
+        port_out = 80
+        eh_port_out = 4567
+        eh_port_in = 0
+        self.nat44_add_address(self.nat_addr)
+        self.nat44_add_address(twice_nat_addr, twice_nat=1)
+        self.nat44_add_static_mapping(self.pg0.remote_ip4, self.nat_addr,
+                                      port_in, port_out, proto=IP_PROTOS.tcp,
+                                      twice_nat=1)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=eh_port_out, dport=port_out))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, self.pg0.remote_ip4)
+            self.assertEqual(ip.src, twice_nat_addr)
+            self.assertEqual(tcp.dport, port_in)
+            self.assertNotEqual(tcp.sport, eh_port_out)
+            eh_port_in = tcp.sport
+            self.check_tcp_checksum(p)
+            self.check_ip_checksum(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+             IP(src=self.pg0.remote_ip4, dst=twice_nat_addr) /
+             TCP(sport=port_in, dport=eh_port_in))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, self.pg1.remote_ip4)
+            self.assertEqual(ip.src, self.nat_addr)
+            self.assertEqual(tcp.dport, eh_port_out)
+            self.assertEqual(tcp.sport, port_out)
+            self.check_tcp_checksum(p)
+            self.check_ip_checksum(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+    def test_twice_nat_lb(self):
+        """ Twice NAT44 local service load balancing """
+        external_addr_n = socket.inet_pton(socket.AF_INET, self.nat_addr)
+        twice_nat_addr = '10.0.1.3'
+        local_port = 8080
+        external_port = 80
+        eh_port_out = 4567
+        eh_port_in = 0
+        server1 = self.pg0.remote_hosts[0]
+        server2 = self.pg0.remote_hosts[1]
+
+        locals = [{'addr': server1.ip4n,
+                   'port': local_port,
+                   'probability': 50},
+                  {'addr': server2.ip4n,
+                   'port': local_port,
+                   'probability': 50}]
+
+        self.nat44_add_address(self.nat_addr)
+        self.nat44_add_address(twice_nat_addr, twice_nat=1)
+
+        self.vapi.nat44_add_del_lb_static_mapping(external_addr_n,
+                                                  external_port,
+                                                  IP_PROTOS.tcp,
+                                                  twice_nat=1,
+                                                  local_num=len(locals),
+                                                  locals=locals)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index,
+                                                  is_inside=0)
+
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=eh_port_out, dport=external_port))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        server = None
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, twice_nat_addr)
+            self.assertIn(ip.dst, [server1.ip4, server2.ip4])
+            if ip.dst == server1.ip4:
+                server = server1
+            else:
+                server = server2
+            self.assertNotEqual(tcp.sport, eh_port_out)
+            eh_port_in = tcp.sport
+            self.assertEqual(tcp.dport, local_port)
+            self.check_tcp_checksum(p)
+            self.check_ip_checksum(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        p = (Ether(src=server.mac, dst=self.pg0.local_mac) /
+             IP(src=server.ip4, dst=twice_nat_addr) /
+             TCP(sport=local_port, dport=eh_port_in))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, self.nat_addr)
+            self.assertEqual(ip.dst, self.pg1.remote_ip4)
+            self.assertEqual(tcp.sport, external_port)
+            self.assertEqual(tcp.dport, eh_port_out)
+            self.check_tcp_checksum(p)
+            self.check_ip_checksum(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+    def test_twice_nat_interface_addr(self):
+        """ Acquire twice NAT44 addresses from interface """
+        self.vapi.nat44_add_interface_addr(self.pg7.sw_if_index, twice_nat=1)
+
+        # no address in NAT pool
+        adresses = self.vapi.nat44_address_dump()
+        self.assertEqual(0, len(adresses))
+
+        # configure interface address and check NAT address pool
+        self.pg7.config_ip4()
+        adresses = self.vapi.nat44_address_dump()
+        self.assertEqual(1, len(adresses))
+        self.assertEqual(adresses[0].ip_address[0:4], self.pg7.local_ip4n)
+        self.assertEqual(adresses[0].twice_nat, 1)
+
+        # remove interface address and check NAT address pool
+        self.pg7.unconfig_ip4()
+        adresses = self.vapi.nat44_address_dump()
+        self.assertEqual(0, len(adresses))
+
     def tearDown(self):
         super(TestNAT44, self).tearDown()
         if not self.vpp_dead: